Spark plug



A. P. SWAIDMARK.

SPARK PLUG.

APPLICATION FILED SEPT. 11. 1920.

Patented Nov. 7, 1922:.

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Patented Nov. 7, 1922.

UNITED STATES 1,434,636 PATENT OFFICE.

ALBIN PEARCE SWAIDMARK, OF I A NCHESTER, NEW HAMPSHIRE.

SPARK rLuG Application filed September 11, 1920. Serial No. 408,581.

T 0 all whom it may concern. 7

Be it known that I, ALBIN P.-SWAIDMARK, a citizen of the United States, and a resident of Manchester, in the county of Hillsborough and State of New Hampshire, have invented a new and useful Spark Plug, of which the following is a full, clear, and exact description.

This invention relates to spark plugs, and has for an object to provide an improved construction in which the dielectric carrying one of the contacts may be reversed in such a manner as to double the life of the same.

Another object of the invention is to provide a reversible dielectric for spark plugs in which a shoulder is rovided near each end so that either end oi the dielectric may be inserted into the plug for acting as the spark end.

A still further object of the invention is to provide a double ended contact rod capable of use with the double ended dielectric or with a single ended dielectric.

In the accompanying drawings Figure 1 is a longitudinal vertical section through a spark plug disclosing an embodiment of the invention.

Figure 2 is a perspective view of a split nut used in Figure 1,

Figure 3 is a sectional View similar to Figure 1 but showing a contact rod and a plug casing of a slightly modified construction.

Referring to the accompanying drawing by numerals 30 indicates acasing which is threaded so as to be screwed into a cylinder in the usual manner and which is provided with shoulders 2 and 3 as well as; with a threaded section 4. The shoulder 2 is de signed to receive the shoulder of either of the cylindrical portions 27 while the threaded section 4 is designed to receive the clamping nut 25 which presses against either portion 27 of the dielectric 21.

As shown in Figure 1 the dielectric 21 is formed with a central reduced section 22 occupying approximately one-third of the length of the dielectric and formed with a groove 23 at each end into which the gasket 24 fits whereby the split clamping bolt 25 may properly press the dielectric in position and against the gasket 26. Adjacent each end of the portion 22 there is provided an annular cylindrical portion 27 merging into a rounded end 28. A conductor rod 29 extends entirely through the dielectric projecting beyond each end and the projecting portions being threaded for receiving suitable clamping nuts. The dielectric 21 is fitted into the casing 30 of thedesired kind which is provided with a contact rod 31 coacting with contact rod 29. When the parts are in the position shown in Figure 1, one end of the dielectric is used but if for any reason that end should be cracked or unusable, the nut 25 could be removed, the dielectric reversed and the nut replaced.

In Figure 3 will be seen another form of rod 47 which is provided with an extra long section 48 for lugs having comparatively long casings. In some engines a plug of this character is necessary. Where the div electric becomes broken at one end in this form of plug and it is necessary to turn the same around, it will be also necessary to remove the rod 47 and turn said rod around so that the-threaded section will always be extending in a position for receiving a conductor clamping nut.

What I claim is 1. A spark" plug of the character described comprising a casing rovided with a shoulder, an internal threaded section, a clamping nut engaging said threaded section, a dielectric formed with a shoulder adjacent each end adapted to engage the shoulder and the casing at different times according to the particular end extending into the casing, an annular flange arranged centrally of the body and adapted to be engaged by said clamping nut for pressing one of said shoulders of the dielectric against the shoulder in the casing, a contact rod extending longitudinally through the dielectric formed with a thread on each end, and a contact section adjacent the threaded section, and a nut adapted to be positioned on the threaded end of said rod arranged exteriorly of the casing.

2. In a spark plug of the character described a casing having an inner shoulder, adielectric formed with a shoulder adjacent each end adapted to have either end inserted into said casing, said dielectric hav ing an annular central bead and a clamping screw engaging said casing, said clamping screw being formed with a flange acting on said bead for clamping the dielectric in said casing.

3, In'a spark plug of the character described a casing provided with an electrode,

a dielectric formed with a shoulder and a said shoulders against the shoulder of the bore on each end said casing being formed I casing and a reversible electrode carried by with a shoulder adapted to co-aet with said dielectric with means positioned in said 10 either of the shoulders on the dielectric ac- ,hores for holding the electrode normally in cording to the end of the dielectirc inserted a fixed'position. v

in the casing, a clamping screw for 'clamping the dielectric in the casing with one of ALBI'N PEARCE SWAIDMARK. 

